Mercury contact stepping switch



pr p. N. M DONALD MERCURY CONTACT STEPPING SWITCH Filed 0c t. l, 1952 FIG I RELEASE POSITION ENERGIZE SOLENOID OPERATED HOME POS. ON 3 RLSE.

Aw mm m mu N N A c N w m F ATTY.

Patented Apr. 27, 1954 MERCURY CONTACT STEPPING SWITCH Duncan N. MacDonald, Arcadia, Calif., assignor to Automatic Electric Laboratories, Inc., Chicago, 111., a corporation of Delaware Application October 1, 1952, Serial No. 312,520

3 Claims.

This invention relates in general to stepping switches for automatic telephony or the like and more particularly to a mercury contact type thereof.

The object of the present invention is to provide an improved stepping switch, of simplified and cheapened construction, whereby, the switch may be actuated by any of the conventional means such as relay mechanism or solenoid or even by manual means.

Cine of the novel and essential features of the invention is the design of a mercury contact switch in which a pool or globule of mercury is caused to travel a closed path within a tube in successive steps, and at each step closes or bridges a pair of contacts.

Another feature lies in the arrangement of the tube in a serie of figure eights lying side by side with the starting and finishing point connected together to thereby form a closed path.

A further feature of the invention resides in the provision of two electrodes at one end of each figure eight projecting through the tube to contact the mercury globule for controlling external circuits.

Still another feature of the invention is the provision for positively preventing the mercury from flowing backwards by insuring that the tube behind the globule is constructed as always being uphill.

These and other objects are accomplished according to the invention, so that each time the switch is oscillated or rocked back and forth, the mercury traverses one figure eight and shorts across its electrodes. reached, the mercury flows out around the return path to its starting position and therefore is ready for another series.

ihe drawing shows methods of carrying out the invention. Similar parts are given the same reference characters in the accompanying figures.

Fig. l is a top view of one embodiment comprising a switch mounted on a rotary ball bearing solenoid with external circuits connected in any desired manner, as circumstances may require.

Fig. 2 is a front view of the device of Fig. 1, showing operated and released positions respectively.

Fig. 3 is a perspective view of the device which indicates energized, released and home positions respectively. It also shows the direction and the path along which the mercury travels.

Fig. 4. is an end view of the device of- Fig. 1, taken from the left side thereof, showing the position of the mercury which travel from home position to operating positions.

When the last position is Referring again to the accompanying drawings a detailed description of the device and its operation are as follows:

The mercury switch as shown in Figs. 1 and 2 is mounted in any desired manner on the armature of a rotary ball bearing solenoid I, so as to be oscillated back and forth as indicated in Fig. 2 in a conventional manner a the solenoid is energized and deenergized. The tube as shown comprises three series of figure eights formed from one continuous length of tubing which may be of glass or the like with the starting and finishing points connected together at 3 to thereby form a closed return path which may be evacuated. At the end of each figure eight such as at points 2, or any other suitable points (not shown) there are two electrode which project through the tube to contact the mercury globule, arranged on the outside for connection to external circuits. It will be understood that the tube may have as many figure eight sections as desired and therefore the switch may successively close as many circuits as desired.

In Fig. 2 an arrangement is shown in which the switch may be rotated clockwise a predetermined distance (say 98) to an operating position. Consequently, the mercury globule contained therein fiows from home position 2 as shown in Fig. 3 to the first energized position l, where it remains until the solenoid is deenergized. When the magnet is deenergized and the switch is rotated back the same degree in the opposite direction, the mercury is positively prevented from flowing backwards, since the tube behind the globule is so constructed as always being uphill, and it, therefore, has no choice but must flow into the second of the series of figure eights, where it stops at the first released position 5 a again clearly shown in Fig. 3. At this point the electrodes indicated at 5 in Fig. l are shorted to control any desired circuit connected thereto. It will be seen now that when the glass tube is again rotated back to the next energized position by the solenoid the mercury will naturally flow from the first released position 5 to the second energized position 6. Similarly, the glass tube, when the magnet i deenergized, will again rotate back the same degree in the opposite position with the result that the mercury will move away from position 6 and stop at the second released position i where a second circuit is closed. As soon as the glass tube i again rotated back to operated position, the mercury will flow out from the second released position 'i around the return path 3 and stop at the third energized position Finally, when the glass tube is again rotated back to the released position, the mercury will likewise move away from the third energized position 8 back to home position 2, which, of course is also the third released position. Therefore, the switch is ready for another series of operation. Obviously, any number of pairs of electrodes may project at either end of each figure eight section, or at any other suitable points thereof as the situation may warrant. It is also understood that any number of convolutions may be provided to suit the number of steps necessary.

Thus successive contacts are made for each oscillation. The device may be used as a stepping' or counting device comprising a multi-contact mercury switch to be tilted back and forth in the same manner with the same function as the conventional type performs except that a plurality of circuits may be successively closed.

Having described in detail the mechanism and the operation thereof in this invention, I do not therefore wish to be limited to the precise embodiment but desire to include and have protected by Letters Patent, all forms of my invention that come within the scope of the appended claims.

What is claimed is:

1. In an automatic switch, a length of tubing containing therein a mercury globule, said tubing being formed into three figure eight sections successively connected in series, each figure eight section comprising a first and a second convolution and the last convolution of the third section being series connected to the first convolution of the first section to form a single continuous path through successive sections for said globule; means for rotating said tube first clockwise and then counterclockwise; said first clockwise rotation causing said globule to how from the first convolution to the second convolution of said first section; said first counterclockwise rotation causing said globule to flow onwards to the first convolution of said second section; the second clockwise rotation causing said globule to flow onwards to the second convolution of said second section; the second counter-clockwise rotation further causing said globule to flow onward to the first convolution of said third section; the third clockwise rotation causing said globule to flow onwards to the second convolution of said third section; the third counter-clockwise rotation causing said globule to flow onwards to the first convolution of the first section, where the globule rests at its home position, and circuit means at the lowermost part of each convolution successively closed and opened by said globule in its travel through said convolutions.

2. In an automatic switch as claimed in claim 1, said convolutions of said tube positively preventing said mercury from flowing backwards around said travel path in order to properly control the sequence of closing and opening said circuit means.

3. In an automatic switch, a length of tubing containing therein a mercury globule, said tubing comprising a plurality of figure eight sections suecessively connected in series, each figure eight section comprising a first and a second convolution and the second convolution of the last section being series connected to the first convolution of the first section to form a single continuous path through the successive sections for said globule; means for rotating said tube in alternate clockwise and counterclockwise rotations; said globule flowing from the first convolution to the second convolution in each section in a predetermined successive order dependent upon the number of said sections being connected in series in response to successive clockwise rotations, said globule flowing from the second convolution of a preceding section to the first convolution of the next succeeding section in response to successive counterclockwise rotations until said globule reaches the first convolution of the first of said sections; and circuit means at the lowermost part of each convolution successively closed and opened by said globule in its travel through successive convoluticns.

References Cited in the file of this patent UNITED STATES PATENTS Number Name Date 907,488 Gabet Dec. 22, 1903 2,440,028 Swisher et a1 Apr. 20, 1948. 

